One of the most common methods for treating abnormal curvature of the spine and spinal disorders is to immobilize a portion of the spine to allow treatment. Traditionally, immobilization has been accomplished by rigid stabilization. For example, in a conventional spinal fusion procedure, a rigid fixation rod is installed between pedicle screws secured to adjacent vertebrae. The fixation rod cooperates with the screws to immobilize the two vertebrae relative to each other so that fusion may occur.
More recently, dynamic stabilization has been used in spinal treatment procedures. Dynamic stabilization permits enhanced mobility of the spine while also providing sufficient stabilization to effect treatment. One example of a dynamic stabilization system is the Dynesys® system available from Zimmer Spine, Inc. of Edina, Minn. Such dynamic stabilization systems typically include a flexible, tubular spacer positioned between pedicle screws installed in adjacent vertebrae of the spine. The spacer is positioned between the pedicle screws and a flexible cord is threaded through the spacer. The flexible cord is also secured to heads of the pedicle screws by set screws, thereby retaining the spacer between the pedicle screws while cooperating with the spacer to permit mobility of the spine.
The dynamic stabilization systems described above and others are installed in a patient during a surgical procedure. Patient recovery from such surgical procedures is greatly enhanced if the tissue, muscle, and other parts of the patient that are displaced and affected by the surgery are minimized, including the size and severity of the required incisions. For example, the cord may be inserted through an incision used to implant one of the pedicle screws and then advanced to its installed position between the pedicle screws. Due to its flexible nature, however, the cord can be difficult to maneuver through the tissue. Therefore, systems and methods that facilitate the insertion of such flexible cords and similar elements are highly desirable.